Originally Posted by Dave Gish (Post 922964)

In addition to conversion time, I believe there is also an issue with image quality. If you de-compress a group of pictures (GOP) and then re-compress to new format that compresses each frame individually, then you've gone through another compression cycle. This will add to mosquito noise and blocking artifacts. Two compression cycles (one for capture, and another for authoring edited output) is already too much, and it usually shows. The only case where it doesn't show is if the capture format is wavelet (i.e. Red 1, SI-2K), or the DCT capture compression is really light (i.e. higher bit rate formats).

You could de-compress a GOP based format like SxS and then create uncompressed files for editing, but the data size on the hard drive would be huge and this would slow down the editing as well.

From what I understand, it's generally best to edit in the format you use to capture, otherwise you will lose quality or speed.

Originally Posted by Robert M Wright (Post 922987)

Cineform works well.

Originally Posted by Dave Gish (Post 922964)

You could de-compress a GOP based format like SxS and then create uncompressed files for editing, but the data size on the hard drive would be huge and this would slow down the editing as well.

Originally Posted by Kevin Shaw (Post 922995)

If you're really concerned about image purity you're arguably better off with a GOP-based recording format, because that can be delivered directly to viewers via Blu-ray or the internet where DVCProHD has to be transcoded for viewing purposes.

Originally Posted by Kevin Shaw (Post 922995)

With hard drives so cheap these days decompressing for editing isn't a problem, and performance is improved significantly (not decreased) in the process.

Originally Posted by Dave Gish (Post 923009)

Uncompressed 1080p video is huge. Moving that much data through the editor will slow things down. With uncompressed footage, it's not the processing intensity, but rather the I/O intensity that slows things down.

Originally Posted by Dave Gish (Post 923009)

To add some dimesions to this, let's say you're doing a 2-hour feature and your shooting ratio is about 10:1. That's 20 hours of raw video. Uncompressed 1080p video is just over 300GB per hour, so that would be over 6 Terabyes for just the raw video.

Originally Posted by Dave Gish (Post 923007)

This is true if you are not doing any editing. When you edit, your edit points will generally be within the GOP, so the video will have to be decompressed and then recompressed. As far as I know, all editors do this internally when authoring output.

Originally Posted by Dave Gish (Post 922993)

Yes. Cineform uses wavelet compression, so it can be used as an intermediate without any noticeable loss in quality.

But from what I've heard, Cineform software costs more than most editors. Around $2000 if I remember correctly.